Ion fluence above which any significant changes in the spectrum, arising from beam damage, are observed in
secondary ion mass spectrometry.
Notes: - Classically, a limit of \(\pu{E12}\) ions per \(\pu{cm2}\), or \(\pu{E16}\) ions per \(\pu{m2}\) is taken as the limit not to be exceeded in static secondary ion mass spectrometry. This limit is based on one incident ion for each \(\pu{1000}\) surface atoms.
- For imaging, the total molecular signal can be used, and here the limit can be greater and reach \(\pu{100}\) times the limit given in Note 1.
- For large molecules, the damage cross section and disappearance cross section are both generally larger than for small molecules, leading to a static limit less than \(\pu{E12}\) ions per \(\pu{cm2}\).
Source:
PAC, 2020, 92, 1781. 'Glossary of methods and terms used in surface chemical analysis (IUPAC Recommendations 2020)' on page 1845 (https://doi.org/10.1515/pac-2019-0404)